1. Field of the Invention
The present invention relates to a technique for analyzing a biotic or biochemical minute sample, such as analysis of DNA (deoxyribonucleic acid) with the use of a technique such as MEMS (Micro Electro Mechanical Systems) or MOEMS (Micro Opto Electro Mechanical Systems).
2. Description of the Background Art
Hitherto, research is made on an apparatus (an apparatus called μTAS or the like) that measures a fluorescence of a sample (a minute substance such as DNA) in a solution flowing through a minute channel to perform various kinds of analysis. In this apparatus, the measurement of fluorescence is realized by individually assembling a light source and an optical system for projecting an excited light to a minute channel and an optical system and an optical detecting element for measuring the fluorescence around the apparatus in which the minute channel has been formed. For this reason, the assembled system as a whole performs a function of an analyzing apparatus.
An example of such an apparatus is disclosed in U.S. Pat. No. 5,858,195. This apparatus is constructed in such a manner that a complex biotic or biochemical operation (analysis or synthesis) to a sample is performed on an analyzing chip (microchip) having a size of about 5 cm×2.5 cm by an electronic control. Specifically, a plurality of water tanks for storing chemical substances and minute channels connecting the plurality of water tanks are formed on an analyzing chip, and each water tank has an individually controlled electric potential, which allows a sample to move through the minute channel among the water tanks.
As a detector that measures a sample, the characteristics and others of the sample can be detected by using, for example, those that detect optical absorption, change in refractive index, fluorescence emission, chemical emission, various Raman spectra, electrical conductivity, electrochemical current, sound wave propagation, or the like.
In performing analysis with the use of an analyzing chip, DNA is divided into fragments having different lengths with a restriction enzyme, and each fragment is allowed to move through a minute channel by electrophoresis. At a certain point in the minute channel, a light such as laser light for exciting a fluorescence is given from the outside and, when a fragment passes through that point, a prescribed fluorescent dye is excited, and the fragment is analyzed by detecting the fluorescence characteristics with a light-receiving optical system disposed on the outside.
However, the prior art technique such as mentioned above involves a problem that the size and the cost of the system as a whole increases because the devices such as the optical system that projects laser light or the like for exciting a fluorescence from the outside of the analyzing chip and the optical system for measuring the fluorescence are disposed around the analyzing chip to allow the system to function as an analyzing system. Further, a lot of labor is required for preparation and position adjustment in disposing each member around the analyzing chip in which the minute channel has been formed, thereby raising a problem that an efficient analysis cannot be carried out.
Moreover, even if an attempt is made to improve the sensitivity or the SN ratio of the fluorescence measurement by adjusting the optical system and others, it reaches a limit at a comparatively low level, and it is difficult to make a further improvement.
Furthermore, in order to repeat a stable analysis with good efficiency, it is desired to perform supply and pick-up of samples, exchange of analyzing chips, and others automatically. Also, in picking up the samples, it is desired to pick up the object samples easily without performing complex manipulations.